Hulk is not in scale. The hands are not much use. However, he's not a bad base figure for something super-muscular and maybe 6'6" or less, like Luke Cage, Rhino, maybe Thor.

I got Venom to make Sub-Mariner. It would be great for Black Panther, as well, so long as you don't care about scale. He'ss taller than Cap, as Venom should be, but close enough for Namor. He could also be Deadpool or Punisher, maybe Sentry. He has the advantage of being cheap. Cap has shot up to the stratosphere. I got like 8 of him before the price went up. Venom has GREAT abs, chest is not too bad.